The present invention relates to a folding knife with safety for blade, and more particularly to a folding knife with an improved safety for blade that does not increase the overall height of the folding knife and can be operated at reduced efforts to ensure a highly safe use of the folding knife.
U.S. patent application Ser. No. 09/512,067 entitled xe2x80x9cFolding Knife with Safety for Bladexe2x80x9d filed by the same inventor of the present invention discloses a safety for blade provided at a first handle cover close to a pivot pin of the folding knife. The safety for blade mainly includes a slip switch, a push element, and an elastic element. The slip switch of the safety for blade is received in a recess formed on the first handle cover close to one side of a hole through which the pivot pin extends. There is a through hole provided in the recess for receiving the push element and the elastic element therein. The recess has an overall configuration matching with that of a top surface of the slip switch but is longer than the slip switch, so that the slip switch could be moved in the recess between a safety unlock and a safety lock position. The slip switch also has a pair of side walls downward extended from two sides of the top surface, such that when the slip switch is received in the recess, the side walls extend into two guide grooves provided at two sides of the recess for the slip switch to move in a direction defined by the guide grooves. Lower edges of the side walls form two hooking means that enable the whole slip switch to slide within the recess without separating therefrom. And, the top surface of the slip switch is provided at an underside with a downward projected protuberance. When the slip switch is moved to the safety lock position, the protuberance extends down into the through hole provided in the recess to interfere with the push element received in the through hole, forcing the push element to lower relative to the first handle cover.
An upper portion of the push element is provided at a top with an inward curved surface. When the slip switch is moved to the safety lock position, the protuberance interferes with the upper portion of the push element and engages a lower end with the inward curved surface, forcing the whole push element to move downward. At this point, a lower lock portion of the push element partially passes through a washer below it to engage into a locking hole formed on the blade to lock the blade in place.
A drawback of the above-described safety for blade is that the use of the push member results in a largely increased thickness of the folding knife that has adverse influence on a convenient operation of the knife. Moreover, when the slip switch is moved to the safety lock position and the protuberance interferes with the upper portion of the push element, there is a considerably large pressure area between the protuberance and the push element that results in increased-friction between these two elements and a user needs to apply increased force to operate the slip switch. It is even possible that the slip switch is stuck and could not be moved further. In the above-described safety for blade, the recess is also provided at a bottom surface with a round dent and the slip switch is provided at the underside with a projected small dot corresponding to the round dent, such that when the slip switch is moved to the safety unlock position, the small dot engages into the round dent to hold the slip switch in the safety unlock position. However, it appears the small dot does not always easily engage with the round dent to hold the slip switch in the safety unlock position and therefore causes inconvenience in the operation of the safety.
It is therefore tried by the inventor to make some modifications in the disclosure of the U.S. patent application Ser. No. 09/512,067 to enable the safety for blade of the folding knife to operate in a smooth manner.
A primary object of the present invention is to provide a folding knife with a safety for blade that does increase an overall height of the folding knife. To achieve this object, the safety for blade includes a lock member having a head portion with a beveled outer periphery and a push block having a beveled lower front, so that the lock member and the push block may be located at substantially the same horizontal plane to, on the one hand, shorten the height of the safety for blade, and on the other hand, allow the push block to smoothly push and depress the lock member to a position capable of locking the blade in place.
Another object of the present invention is to provide a folding knife with safety for blade, in which a push block having two notches provided at one side thereof and an elastic strip buried in a handle cover of the folding knife with a V-shaped projection extended toward the notches on the push block are included. When the push block is moved forward or backward to a safety lock position or a safety unlock position, the V-shaped projection of the elastic strip engages into one of the two notches to automatically hold the push block in place. Due to the elastic strip, a reduced frictional resistance of the V-shaped projection to the push block is possible when the projection engages into or disengages from the notches. The safety for blade can therefore be operated smoothly.